Critically ill patients often lose their ability to ingest normal amounts of food necessary to maintain adequate nutritional levels. Typical of such patients are those having various oroesophageal cancers, strokes, neuromuscular dystrophy and Parkinson's Disease. Many cancer therapy routines require periods of abstinence. Other cancer therapies often cause nausea and vomiting which result in the interruption of a patient's normal eating habits. Obviously, such patients become malnourished and resort must be had to some form of hyperalimentation in order to sustain the patient. Enteral hyperalimentation is usually the treatment of choice since it produces fewer side effects than the introduction of nutrients directly into a vein.
The compositions presently marketed as complete therapeutic diets for enteral hyperalimentation all contain 2 Kcal/ml or less. These products have a low fat and high carbohydrate content. Carbohydrates are osmotically more active than fats. Low fat diets have a higher osmolality which frequently leads to diarrhea. This reduces the feeding load of such products to less than 3500 Kcal/24 hours. Also, the lower caloric density of low fat diets precludes higher intake because of the volume limitations. Although central vein hyperalimentation can provide more energy and nutrients, this mode of feeding has frequent serious side effects which limit the intake to below 4000 Kcal/24 hours.
Compositions which would provide a higher caloric intake via enteral hyperalimentation without side effects would obviously be desirable. Heretofore, such compositions have been unknown. Low fat content of the presently available diets is based on the observation of increased stool fat in malabsorption. (See Davis-Christopher Textbook of Surgery, Ed. D. C. Sabiston, Jr., W. B. Saunders Co., Philadelphia, Pa., (1977) p. 1021; Clinics In Gastroenterology, 8, 373 (1979); Gastrointestinal Disease, II, 2nd. Ed., W. B. Saunders Co., Philadelphia, Pa., (1978), "The Short Bowel Syndrome", Trier, 1137). This accepted clinical judgment completely neglects that with increasing intake of dietary fat there is a linear increase in the absorption of fat. A great example from the nature the very high fat content of breast milk provided for the first weeks of life has not been conceptually considered in the development of routinely available diets.